No it is not. I believe that there should be no commas. So...
Newton and others should have realized that a static universe would soon start contracting.
Commas mean that there is a brief pause, and it just doesn't sound right with a pause in this sentence.
number 5 (his own creative brain) is your answer.
The answer is because and since. A subordinating conjunction joins a subordinate condition to a fundamental statement. The accompanying is a rundown of the most widely recognized subordinating conjunctions. A qualifier condition is constantly presented by a subordinating conjunction. A thing statement and descriptive word condition in some cases are.
